As fork support device for a bicycle mounted on a conventional automobile, for example, Japanese Unexamined Patent Application Publication No. 7-10054 illustrated in FIG. 38 discloses the following configuration. A fork support device 300 is secured to a carrier bar 12 placed on the roof of an automobile. The bicycle includes a pair of conventional forks 20 where inverse U-shaped groove portions 21 are formed in the lower portions. The groove portion 21 of the conventional fork 20 is formed to allow accepting a support shaft 302 of a quick release skewer 301, which supports the hub of the wheel of the bicycle. The fork support device 300 includes: a fork base 303, which holds the support shaft 302 to allow free insertion of the support shaft 302; a support surface 304, which is arranged in one end portion of the support shaft 302 and can push one of the conventional forks 20 from the side surface; and an adjusting knob 306, which is threadably mounted on a screw portion 305 formed in the other end portion of the support shaft 302. The rotation operation of a lever 307 arranged between the fork base 303 and the adjusting knob 306 causes movement of the support shaft 302 to the lever 307 side, so as to secure the conventional forks 20 of the bicycle to the fork support device 300.
However, like Japanese Unexamined Patent Application Publication No. 7-10054, the drawback of the conventional structure where the conventional forks 20 of the conventional bicycle are secured by the support shaft 302 of the quick release skewer 301 is that a lot of types of mountain bikes and off-road bicycles cannot be secured. As the reason, since many mountain bikes and off-road bicycles employ through-axle wheels, these bikes do not have the inverse U-shaped groove portions 21 of the conventional forks 20 and include a closed opening portion, which receives an axle, a wheel hub member, or a hole cylinder, in the end positions of through-axle forks, which hold the through-axle wheels. Accordingly, the conventional fork support device 300, which is designed to secure the conventional fork 20, cannot secure a through axle for securing through-axle hubs with different outer diameters.
Accordingly, Japanese Unexamined Patent Application Publication No. 2004-161020 illustrated in FIG. 39 and FIG. 40 discloses the following technology. A fork support device 310 is secured to the carrier bar 12. For a downhill type bicycle, to secure the forks of a bicycle using a through axle with a diameter of, for example, 20 mm, an intermediate rod 312, which has an inner diameter fitting the outer diameter of a fork supporting shaft 311 for holding the conventional forks 20 of the bicycle, is changed corresponding to the through axle. Accordingly, the forks of the downhill type bicycle are directly secured to a supporting unit 313.
In Japanese Translation of PCT International Application Publication No. JP-T-2009-506921 illustrated in FIGS. 41, 42, and 43, a fork support device 330 is secured to the carrier bar 12. The fork support device 330 is configured to allow securing both of: the conventional forks 20 secured by the support shaft of the conventional quick release skewer, and a through-axle fork 331 secured by a through axle. As this fork support device 330, a disclosed fork support device includes a hole 334 formed in a fork mount to allow passage of a through-axle fork adaptor 332 or a conventional fork adaptor 333 and house this adaptor.
Here, in both Japanese Unexamined Patent Application Publication No. 2004-161020 and Japanese Translation of PCT International Application Publication No. JP-T-2009-506921 where the through-axle fork can be secured, there is no antitheft means for a bicycle of a through axle type.    Patent Document 1: Japanese Unexamined Patent Application Publication No. 7-10054    Patent Document 2: Japanese Unexamined Patent Application Publication No. 2004-161020    Patent Document 3: Japanese Translation of PCT International Application Publication No. JP-T-2009-506921